标准库头文件 <string>

 

C++

语言

标准库头文件

自立与有宿主实现

具名要求

语言支持库

概念库 (C++20)

诊断库

工具库

字符串库

容器库

迭代器库

范围库 (C++20)

算法库

数值库

输入/输出库

本地化库

正则表达式库 (C++11)

原子操作库 (C++11)

线程支持库 (C++11)

文件系统库 (C++17)

技术规范

 

标准库头文件

语言支持
<cstddef> <limits> <climits> <coroutine>	<cfloat> <cstdint> <new> <source_location>	<typeinfo> <exception> <initializer_list> <version>	<csignal> <csetjmp> <cstdarg>
概念
<concepts>
诊断
<stdexcept>	<cassert>	<cerrno>	<system_error>
通用工具
<utility> <memory> <memory_resource> <scoped_allocator>     <compare>	<bitset> <tuple> <optional> <any> <variant>	<type_traits> <ratio> <chrono> <typeindex> <functional>	<ctime> <cstdlib>
字符串
<string> <string_view> <cstring>	<charconv> <format>	<cctype> <cwctype>	<cwchar> <cuchar>
本地化
<locale>	<codecvt>	<clocale>
容器
<span> <array> <vector>	<deque> <forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
迭代器
<iterator>
范围
<ranges>
算法
<algorithm>	<execution>
数值
<complex> <random>	<valarray> <numeric>	<bit> <numbers>	<cfenv> <cmath>
输入/输出
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<sstream> <fstream> <syncstream>	<cstdio> <cinttypes> <strstream>
正则表达式
<regex>
文件系统
<filesystem>
线程支持
<thread> <atomic> <mutex>	<shared_mutex> <condition_variable> <future>	<stop_token> <semaphore>	<latch> <barrier>
C 兼容
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

 

此头文件是字符串库的一部分。

包含

<initializer_list>

(C++11 起)

类

名称	描述
std::char_traits	描述字符类型的性质的类模板(类模板)
std::char_traits<char>	(类模板特化)
std::char_traits<wchar_t>	(类模板特化)
std::char_traits<char8_t> (C++20)	(类模板特化)
std::char_traits<char16_t> (C++11)	(类模板特化)
std::char_traits<char32_t> (C++11)	(类模板特化)
std::basic_string	表示文本字符串对象的类模板(类模板)
std::string	std::basic_string<char> (typedef)
std::u8string (C++20)	std::basic_string<char8_t> (typedef)
std::u16string (C++11)	std::basic_string<char16_t> (typedef)
std::u32string (C++11)	std::basic_string<char32_t> (typedef)
std::wstring	std::basic_string<wchar_t> (typedef)
std::pmr::basic_string (C++17)	(别名模板)
std::pmr::string (C++17)	std::pmr::basic_string<char> (typedef)
std::pmr::u8string (C++20)	std::pmr::basic_string<char8_t> (typedef)
std::pmr::u16string (C++17)	std::pmr::basic_string<char16_t> (typedef)
std::pmr::u32string (C++17)	std::pmr::basic_string<char32_t> (typedef)
std::pmr::wstring (C++17)	std::pmr::basic_string<wchar_t> (typedef)
std::hash<std::string> (C++11)	(类模板特化)
std::hash<std::u8string> (C++20)	(类模板特化)
std::hash<std::u16string> (C++11)	(类模板特化)
std::hash<std::u32string> (C++11)	(类模板特化)
std::hash<std::wstring> (C++11)	(类模板特化)
std::hash<std::pmr::string> (C++20)	(类模板特化)
std::hash<std::pmr::u8string> (C++20)	(类模板特化)
std::hash<std::pmr::u16string> (C++20)	(类模板特化)
std::hash<std::pmr::u32string> (C++20)	(类模板特化)
std::hash<std::pmr::wstring> (C++20)	(类模板特化)

函数

operator+	连接两个字符串或者一个字符串和一个字符 (函数模板)
operator==operator!=operator<operator>operator<=operator>=	以字典序比较两个字符串 (函数模板)
std::swap(std::basic_string)	特化 std::swap 算法 (函数模板)
输入/输出
operator<<operator>>	执行字符串的流输入与输出 (函数模板)
getline	从 I/O 流读取数据到字符串 (函数模板)
数值转换
stoistolstoll (C++11)(C++11)(C++11)	转换字符串为有符号整数 (函数)
stoulstoull (C++11)(C++11)	转换字符串为无符号整数 (函数)
stofstodstold (C++11)(C++11)(C++11)	转换字符串为浮点值 (函数)
to_string (C++11)	转换整数或浮点值为 string (函数)
to_wstring (C++11)	转换整数或浮点值为 wstring (函数)

字面量

定义于内联命名空间 std::literals::string_literals
operator""s (C++14)	转换字符数组字面量为 basic_string (函数)

概要

#include <initializer_list>
namespace std {
  // 字符特征
  template<class charT> struct char_traits;
  template<> struct char_traits<char>;
  template<> struct char_traits<char8_t>;
  template<> struct char_traits<char16_t>;
  template<> struct char_traits<char32_t>;
  template<> struct char_traits<wchar_t>;
  // basic_string
  template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT>>
  class basic_string;
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(const basic_string<charT, traits, Allocator>& lhs, const basic_string<charT, traits, Allocator>& rhs);
template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(basic_string<charT, traits, Allocator>&& lhs, const basic_string<charT, traits, Allocator>& rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(const basic_string<charT, traits, Allocator>& lhs, basic_string<charT, traits, Allocator>&& rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(basic_string<charT, traits, Allocator>&& lhs,
basic_string<charT, traits, Allocator>&& rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(const charT* lhs, basic_string<charT, traits, Allocator>&& rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(charT lhs, const basic_string<charT, traits, Allocator>& rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(charT lhs, basic_string<charT, traits, Allocator>&& rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(basic_string<charT, traits, Allocator>&& lhs,
const charT* rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(const basic_string<charT, traits, Allocator>& lhs, charT rhs);
  template<class charT, class traits, class Allocator>
  basic_string<charT, traits, Allocator> operator+(basic_string<charT, traits, Allocator>&& lhs, charT rhs);
  template<class charT, class traits, class Allocator>
  bool operator==(const basic_string<charT, traits, Allocator>& lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
  template<class charT, class traits, class Allocator>
  bool operator==(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs);
  template<class charT, class traits, class Allocator>
  bool operator==(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
  template<class charT, class traits, class Allocator>
  bool operator!=(const basic_string<charT, traits, Allocator>& lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
  template<class charT, class traits, class Allocator>
  bool operator!=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs);
  template<class charT, class traits, class Allocator>
  bool operator!=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
  template<class charT, class traits, class Allocator>
  bool operator< (const basic_string<charT, traits, Allocator>& lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
  template<class charT, class traits, class Allocator>
  bool operator< (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
  template<class charT, class traits, class Allocator>
  bool operator< (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs);
  template<class charT, class traits, class Allocator>
  bool operator> (const basic_string<charT, traits, Allocator>& lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
  template<class charT, class traits, class Allocator>
  bool operator> (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
template<class charT, class traits, class Allocator>
  bool operator> (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs);
  template<class charT, class traits, class Allocator>
  bool operator<=(const basic_string<charT, traits, Allocator>& lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
  template<class charT, class traits, class Allocator>
  bool operator<=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
  template<class charT, class traits, class Allocator>
  bool operator<=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs);
  template<class charT, class traits, class Allocator>
  bool operator>=(const basic_string<charT, traits, Allocator>& lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
  template<class charT, class traits, class Allocator>
  bool operator>=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
  template<class charT, class traits, class Allocator>
  bool operator>=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs);
  // swap
  template<class charT, class traits, class Allocator>
  void swap(basic_string<charT, traits, Allocator>& lhs, basic_string<charT, traits, Allocator>& rhs) noexcept(noexcept(lhs.swap(rhs)));
  // 插入符与提取符
  template<class charT, class traits, class Allocator>
  basic_istream<charT, traits>& operator>>(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
  template<class charT, class traits, class Allocator>
  basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& os, const basic_string<charT, traits, Allocator>& str);
  template<class charT, class traits, class Allocator> basic_istream<charT, traits>& getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str,
charT delim);
  template<class charT, class traits, class Allocator>
  basic_istream<charT, traits>& getline(basic_istream<charT, traits>&& is, basic_string<charT, traits, Allocator>& str, charT delim);
  template<class charT, class traits, class Allocator>
  basic_istream<charT, traits>& getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
  template<class charT, class traits, class Allocator>
  basic_istream<charT, traits>& getline(basic_istream<charT, traits>&& is, basic_string<charT, traits, Allocator>& str);
  // basic_string typedef 名
  using string = basic_string<char>;
  using u8string = basic_string<char8_t>;
  using u16string = basic_string<char16_t>;
  using u32string = basic_string<char32_t>;
  using wstring = basic_string<wchar_t>;
  // 数值转换
  int stoi(const string& str, size_t* idx = 0, int base = 10);
  long stol(const string& str, size_t* idx = 0, int base = 10);
  unsigned long stoul(const string& str, size_t* idx = 0, int base = 10);
  long long stoll(const string& str, size_t* idx = 0, int base = 10);
  unsigned long long stoull(const string& str, size_t* idx = 0, int base = 10);
  float stof(const string& str, size_t* idx = 0);
  double stod(const string& str, size_t* idx = 0);
  long double stold(const string& str, size_t* idx = 0);
  string to_string(int val);
  string to_string(unsigned val);
  string to_string(long val);
  string to_string(unsigned long val);
  string to_string(long long val);
  string to_string(unsigned long long val);
  string to_string(float val);
  string to_string(double val);
  string to_string(long double val);
  int stoi(const wstring& str, size_t* idx = 0, int base = 10);
  long stol(const wstring& str, size_t* idx = 0, int base = 10);
  unsigned long stoul(const wstring& str, size_t* idx = 0, int base = 10);
  long long stoll(const wstring& str, size_t* idx = 0, int base = 10);
  unsigned long long stoull(const wstring& str, size_t* idx = 0, int base = 10);
  float stof(const wstring& str, size_t* idx = 0);
  double stod(const wstring& str, size_t* idx = 0);
  long double stold(const wstring& str, size_t* idx = 0);
  wstring to_wstring(int val);
  wstring to_wstring(unsigned val);
  wstring to_wstring(long val);
  wstring to_wstring(unsigned long val);
  wstring to_wstring(long long val);
  wstring to_wstring(unsigned long long val);
  wstring to_wstring(float val);
  wstring to_wstring(double val);
  wstring to_wstring(long double val);
  namespace pmr {
    template <class charT, class traits = char_traits<charT>>
    using basic_string = std::basic_string<charT, traits, polymorphic_allocator<charT>>;
    using string = basic_string<char>;
    using u8string = basic_string<char8_t>;
    using u16string = basic_string<char16_t>;
    using u32string = basic_string<char32_t>;
    using wstring = basic_string<wchar_t>;
  }
  // 散列支持
  template<class T> struct hash;
  template<> struct hash<string>;
  template<> struct hash<u8string>;
  template<> struct hash<u16string>;
  template<> struct hash<u32string>;
  template<> struct hash<wstring>;
  template<> struct hash<pmr::string>;
  template<> struct hash<pmr::u8string>;
  template<> struct hash<pmr::u16string>;
  template<> struct hash<pmr::u32string>;
  template<> struct hash<pmr::wstring>;
  inline namespace literals {
    inline namespace string_literals {
      // basic_string 字面量的后缀
      string operator""s(const char* str, size_t len);
      u8string operator""s(const char8_t* str, size_t len);
      u16string operator""s(const char16_t* str, size_t len);
      u32string operator""s(const char32_t* str, size_t len);
      wstring operator""s(const wchar_t* str, size_t len);
    }
  }
}

类模板 std::char_traits

namespace std {
  template<> struct char_traits<char> {
    using char_type = char;
    using int_type = int;
    using off_type = streamoff;
    using pos_type = streampos;
    using state_type = mbstate_t;
    static constexpr void assign(char_type& c1, const char_type& c2) noexcept;
    static constexpr bool eq(char_type c1, char_type c2) noexcept;
    static constexpr bool lt(char_type c1, char_type c2) noexcept;
    static constexpr int compare(const char_type* s1, const char_type* s2, size_t n);
    static constexpr size_t length(const char_type* s);
    static constexpr const char_type* find(const char_type* s, size_t n, const char_type& a);
    static constexpr char_type* move(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* copy(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* assign(char_type* s, size_t n, char_type a);
    static constexpr int_type not_eof(int_type c) noexcept;
    static constexpr char_type to_char_type(int_type c) noexcept;
    static constexpr int_type to_int_type(char_type c) noexcept;
    static constexpr bool eq_int_type(int_type c1, int_type c2) noexcept;
    static constexpr int_type eof() noexcept;
  };
 
  template<> struct char_traits<char8_t> {
    using char_type = char8_t;
    using int_type = unsigned int;
    using off_type = streamoff;
    using pos_type = u8streampos;
    using state_type = mbstate_t;
    static constexpr void assign(char_type& c1, const char_type& c2) noexcept;
    static constexpr bool eq(char_type c1, char_type c2) noexcept;
    static constexpr bool lt(char_type c1, char_type c2) noexcept;
    static constexpr int compare(const char_type* s1, const char_type* s2, size_t n);
    static constexpr size_t length(const char_type* s);
    static constexpr const char_type* find(const char_type* s, size_t n, const char_type& a);
    static constexpr char_type* move(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* copy(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* assign(char_type* s, size_t n, char_type a);
    static constexpr int_type not_eof(int_type c) noexcept;
    static constexpr char_type to_char_type(int_type c) noexcept;
    static constexpr int_type to_int_type(char_type c) noexcept;
    static constexpr bool eq_int_type(int_type c1, int_type c2) noexcept;
    static constexpr int_type eof() noexcept;
  };
 
  template<> struct char_traits<char16_t> {
    using char_type = char16_t;
    using int_type = uint_least16_t;
    using off_type = streamoff;
    using pos_type = u16streampos;
    using state_type = mbstate_t;
    static constexpr void assign(char_type& c1, const char_type& c2) noexcept;
    static constexpr bool eq(char_type c1, char_type c2) noexcept;
    static constexpr bool lt(char_type c1, char_type c2) noexcept;
    static constexpr int compare(const char_type* s1, const char_type* s2, size_t n);
    static constexpr size_t length(const char_type* s);
    static constexpr const char_type* find(const char_type* s, size_t n, const char_type& a);
    static constexpr char_type* move(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* copy(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* assign(char_type* s, size_t n, char_type a);
    static constexpr int_type not_eof(int_type c) noexcept;
    static constexpr char_type to_char_type(int_type c) noexcept;
    static constexpr int_type to_int_type(char_type c) noexcept;
    static constexpr bool eq_int_type(int_type c1, int_type c2) noexcept;
    static constexpr int_type eof() noexcept;
  };
 
  template<> struct char_traits<char32_t> {
    using char_type = char32_t;
    using int_type = uint_least32_t;
    using off_type = streamoff;
    using pos_type = u32streampos;
    using state_type = mbstate_t;
    static constexpr void assign(char_type& c1, const char_type& c2) noexcept;
    static constexpr bool eq(char_type c1, char_type c2) noexcept;
    static constexpr bool lt(char_type c1, char_type c2) noexcept;
    static constexpr int compare(const char_type* s1, const char_type* s2, size_t n);
    static constexpr size_t length(const char_type* s);
    static constexpr const char_type* find(const char_type* s, size_t n, const char_type& a);
    static constexpr char_type* move(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* copy(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* assign(char_type* s, size_t n, char_type a);
    static constexpr int_type not_eof(int_type c) noexcept;
    static constexpr char_type to_char_type(int_type c) noexcept;
    static constexpr int_type to_int_type(char_type c) noexcept;
    static constexpr bool eq_int_type(int_type c1, int_type c2) noexcept;
    static constexpr int_type eof() noexcept;
  };
 
  template<> struct char_traits<wchar_t> {
    using char_type = wchar_t;
    using int_type = wint_t;
    using off_type = streamoff;
    using pos_type = wstreampos;
    using state_type = mbstate_t;
    static constexpr void assign(char_type& c1, const char_type& c2) noexcept;
    static constexpr bool eq(char_type c1, char_type c2) noexcept;
    static constexpr bool lt(char_type c1, char_type c2) noexcept;
    static constexpr int compare(const char_type* s1, const char_type* s2, size_t n);
    static constexpr size_t length(const char_type* s);
    static constexpr const char_type* find(const char_type* s, size_t n, const char_type& a);
    static constexpr char_type* move(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* copy(char_type* s1, const char_type* s2, size_t n);
    static constexpr char_type* assign(char_type* s, size_t n, char_type a);
    static constexpr int_type not_eof(int_type c) noexcept;
    static constexpr char_type to_char_type(int_type c) noexcept;
    static constexpr int_type to_int_type(char_type c) noexcept;
    static constexpr bool eq_int_type(int_type c1, int_type c2) noexcept;
    static constexpr int_type eof() noexcept;
  };
}

类模板 std::basic_string

namespace std {
  template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT>>
  class basic_string {
  public:
    // 类型：
    using traits_type = traits;
    using value_type = charT;
    using allocator_type = Allocator;
    using size_type = typename allocator_traits<Allocator>::size_type;
    using difference_type = typename allocator_traits<Allocator>::difference_type;
    using pointer = typename allocator_traits<Allocator>::pointer;
    using const_pointer = typename allocator_traits<Allocator>::const_pointer;
    using reference = value_type&;
    using const_reference = const value_type&;
    using iterator = /* 见定义 */ ;
    using const_iterator = /* 见定义 */ ;
    using reverse_iterator = std::reverse_iterator<iterator>;
    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
    static const size_type npos = -1;
    // 构造/复制/销毁
    basic_string() noexcept(noexcept(Allocator())) : basic_string(Allocator()) { }
    explicit basic_string(const Allocator& a) noexcept;
    basic_string(const basic_string& str);
    basic_string(basic_string&& str) noexcept;
    basic_string(const basic_string& str, size_type pos, const Allocator& a = Allocator());
    basic_string(const basic_string& str, size_type pos, size_type n, const Allocator& a = Allocator());
    template<class T>
    basic_string(const T& t, size_type pos, size_type n, const Allocator& a = Allocator());
    explicit basic_string(basic_string_view<charT, traits> sv, const Allocator& a = Allocator());
    basic_string(const charT* s, size_type n, const Allocator& a = Allocator());
    basic_string(const charT* s, const Allocator& a = Allocator());
    basic_string(size_type n, charT c, const Allocator& a = Allocator());
    template<class InputIt>
    basic_string(InputIt begin, InputIt end, const Allocator& a = Allocator());
    basic_string(initializer_list<charT>, const Allocator& = Allocator());
    basic_string(const basic_string&, const Allocator&);
    basic_string(basic_string&&, const Allocator&);
    ~basic_string();
    basic_string& operator=(const basic_string& str);
    basic_string& operator=(basic_string&& str) noexcept(allocator_traits<Allocator>::propagate_on_container_move_assignment::value ||
allocator_traits<Allocator>::is_always_equal::value);
    basic_string& operator=(basic_string_view<charT, traits> sv);
    basic_string& operator=(const charT* s);
    basic_string& operator=(charT c);
    basic_string& operator=(initializer_list<charT>);
    // 迭代器
    iterator begin() noexcept;
    const_iterator begin() const noexcept;
    iterator end() noexcept;
    const_iterator end() const noexcept;
    reverse_iterator rbegin() noexcept;
    const_reverse_iterator rbegin() const noexcept;
    reverse_iterator rend() noexcept;
    const_reverse_iterator rend() const noexcept;
    const_iterator cbegin() const noexcept;
    const_iterator cend() const noexcept;
    const_reverse_iterator crbegin() const noexcept;
    const_reverse_iterator crend() const noexcept;
    // 容量
    size_type size() const noexcept;
    size_type length() const noexcept;
    size_type max_size() const noexcept;
    void resize(size_type n, charT c);
    void resize(size_type n);
    size_type capacity() const noexcept;
    void reserve(size_type res_arg = 0);
    void shrink_to_fit();
    void clear() noexcept;
    [[nodiscard]] bool empty() const noexcept;
    // 元素访问
    const_reference operator[](size_type pos) const;
    reference operator[](size_type pos);
    const_reference at(size_type n) const;
    reference at(size_type n);
    const charT& front() const;
    charT& front();
    const charT& back() const;
    charT& back();
    // 修改器
    basic_string& operator+=(const basic_string& str);
    basic_string& operator+=(basic_string_view<charT, traits> sv);
    basic_string& operator+=(const charT* s);
    basic_string& operator+=(charT c);
    basic_string& operator+=(initializer_list<charT>);
    basic_string& append(const basic_string& str);
    basic_string& append(const basic_string& str, size_type pos, size_type n = npos);
    basic_string& append(basic_string_view<charT, traits> sv);
    template<class T>
    basic_string& append(const T& t, size_type pos, size_type n = npos);
    basic_string& append(const charT* s, size_type n);
    basic_string& append(const charT* s);
    basic_string& append(size_type n, charT c);
    template<class InputIt>
    basic_string& append(InputIt first, InputIt last);
    basic_string& append(initializer_list<charT>);
    void push_back(charT c);
    basic_string& assign(const basic_string& str);
    basic_string& assign(basic_string&& str) noexcept(allocator_traits<Allocator>::propagate_on_container_move_assignment::value ||
allocator_traits<Allocator>::is_always_equal::value);
    basic_string& assign(const basic_string& str, size_type pos, size_type n = npos);
    basic_string& assign(basic_string_view<charT, traits> sv);
    template<class T>
    basic_string& assign(const T& t, size_type pos, size_type n = npos);
    basic_string& assign(const charT* s, size_type n);
    basic_string& assign(const charT* s);
    basic_string& assign(size_type n, charT c);
    template<class InputIt>
    basic_string& assign(InputIt first, InputIt last);
    basic_string& assign(initializer_list<charT>);
    basic_string& insert(size_type pos, const basic_string& str);
    basic_string& insert(size_type pos1, const basic_string& str, size_type pos2, size_type n = npos);
    basic_string& insert(size_type pos, basic_string_view<charT, traits> sv);
    template<class T>
    basic_string& insert(size_type pos1, const T& t, size_type pos2, size_type n = npos);
    basic_string& insert(size_type pos, const charT* s, size_type n);
    basic_string& insert(size_type pos, const charT* s);
    basic_string& insert(size_type pos, size_type n, charT c);
    iterator insert(const_iterator p, charT c);
    iterator insert(const_iterator p, size_type n, charT c);
    template<class InputIt>
    iterator insert(const_iterator p, InputIt first, InputIt last);
    iterator insert(const_iterator p, initializer_list<charT>);
    basic_string& erase(size_type pos = 0, size_type n = npos);
    iterator erase(const_iterator p);
    iterator erase(const_iterator first, const_iterator last);
    void pop_back();
    basic_string& replace(size_type pos1, size_type n1, const basic_string& str);
    basic_string& replace(size_type pos1, size_type n1, const basic_string& str, size_type pos2, size_type n2 = npos);
    basic_string& replace(size_type pos1, size_type n1, basic_string_view<charT, traits> sv);
    template<class T>
    basic_string& replace(size_type pos1, size_type n1, const T& t, size_type pos2, size_type n2 = npos);
    basic_string& replace(size_type pos, size_type n1, const charT* s, size_type n2);
    basic_string& replace(size_type pos, size_type n1, const charT* s);
    basic_string& replace(size_type pos, size_type n1, size_type n2, charT c);
    basic_string& replace(const_iterator i1, const_iterator i2, const basic_string& str);
    basic_string& replace(const_iterator i1, const_iterator i2, basic_string_view<charT, traits> sv);
    basic_string& replace(const_iterator i1, const_iterator i2, const charT* s, size_type n);
    basic_string& replace(const_iterator i1, const_iterator i2, const charT* s);
    basic_string& replace(const_iterator i1, const_iterator i2, size_type n, charT c);
    template<class InputIt>
    basic_string& replace(const_iterator i1, const_iterator i2, InputIt j1, InputIt j2);
    basic_string& replace(const_iterator, const_iterator, initializer_list<charT>);
    size_type copy(charT* s, size_type n, size_type pos = 0) const;
    void swap(basic_string& str) noexcept(allocator_traits<Allocator>::propagate_on_container_swap::value ||
allocator_traits<Allocator>::is_always_equal::value);
    // 字符串操作
    const charT* c_str() const noexcept;
    const charT* data() const noexcept;
    charT* data() noexcept;
    operator basic_string_view<charT, traits>() const noexcept;
    allocator_type get_allocator() const noexcept;
    size_type find (basic_string_view<charT, traits> sv, size_type pos = 0) const noexcept;
    size_type find (const basic_string& str, size_type pos = 0) const noexcept;
    size_type find (const charT* s, size_type pos, size_type n) const;
    size_type find (const charT* s, size_type pos = 0) const;
    size_type find (charT c, size_type pos = 0) const;
    size_type rfind(basic_string_view<charT, traits> sv, size_type pos = npos) const noexcept;
    size_type rfind(const basic_string& str, size_type pos = npos) const noexcept;
    size_type rfind(const charT* s, size_type pos, size_type n) const;
    size_type rfind(const charT* s, size_type pos = npos) const;
    size_type rfind(charT c, size_type pos = npos) const;
    size_type find_first_of(basic_string_view<charT, traits> sv, size_type pos = 0) const noexcept;
    size_type find_first_of(const basic_string& str, size_type pos = 0) const noexcept;
    size_type find_first_of(const charT* s, size_type pos, size_type n) const;
    size_type find_first_of(const charT* s, size_type pos = 0) const;
    size_type find_first_of(charT c, size_type pos = 0) const;
    size_type find_last_of (basic_string_view<charT, traits> sv, size_type pos = npos) const noexcept;
    size_type find_last_of (const basic_string& str, size_type pos = npos) const noexcept;
    size_type find_last_of (const charT* s, size_type pos, size_type n) const;
    size_type find_last_of (const charT* s, size_type pos = npos) const;
    size_type find_last_of (charT c, size_type pos = npos) const;
    size_type find_first_not_of(basic_string_view<charT, traits> sv, size_type pos = 0) const noexcept;
    size_type find_first_not_of(const basic_string& str, size_type pos = 0) const noexcept;
    size_type find_first_not_of(const charT* s, size_type pos, size_type n) const;
    size_type find_first_not_of(const charT* s, size_type pos = 0) const;
    size_type find_first_not_of(charT c, size_type pos = 0) const;
    size_type find_last_not_of (basic_string_view<charT, traits> sv, size_type pos = npos) const noexcept;
    size_type find_last_not_of (const basic_string& str, size_type pos = npos) const noexcept;
    size_type find_last_not_of (const charT* s, size_type pos, size_type n) const;
    size_type find_last_not_of (const charT* s, size_type pos = npos) const;
    size_type find_last_not_of (charT c, size_type pos = npos) const;
    basic_string substr(size_type pos = 0, size_type n = npos) const;
    int compare(basic_string_view<charT, traits> sv) const noexcept;
    int compare(size_type pos1, size_type n1,
    basic_string_view<charT, traits> sv) const;
    template<class T>
    int compare(size_type pos1, size_type n1, const T& t, size_type pos2, size_type n2 = npos) const;
    int compare(const basic_string& str) const noexcept;
    int compare(size_type pos1, size_type n1, const basic_string& str) const;
    int compare(size_type pos1, size_type n1, const basic_string& str, size_type pos2, size_type n2 = npos) const;
    int compare(const charT* s) const;
    int compare(size_type pos1, size_type n1, const charT* s) const;
    int compare(size_type pos1, size_type n1, const charT* s, size_type n2) const;
    bool starts_with(basic_string_view<charT, traits> x) const noexcept;
    bool starts_with(charT x) const noexcept;
    bool starts_with(const charT* x) const;
    bool ends_with(basic_string_view<charT, traits> x) const noexcept;
    bool ends_with(charT x) const noexcept;
    bool ends_with(const charT* x) const;
  };
  template<class InputIt,
  class Allocator = allocator<typename iterator_traits<InputIt>::value_type>>
  basic_string(InputIt, InputIt, Allocator = Allocator())
  -> basic_string<typename iterator_traits<InputIt>::value_type,
                  char_traits<typename iterator_traits<InputIt>::value_type>,
                  Allocator>;
}